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Questions and Answers
What is the primary function of microfilaments in eukaryotic cells?
What is the primary function of microfilaments in eukaryotic cells?
Which structure is responsible for organizing microtubules during mitosis in animal cells?
Which structure is responsible for organizing microtubules during mitosis in animal cells?
What distinguishes intermediate filaments from microtubules and microfilaments?
What distinguishes intermediate filaments from microtubules and microfilaments?
What is the structural composition of microtubules?
What is the structural composition of microtubules?
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In which location within the mitochondrion can the mitochondrial DNA be found?
In which location within the mitochondrion can the mitochondrial DNA be found?
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What did Francesco Redi's experiments primarily demonstrate?
What did Francesco Redi's experiments primarily demonstrate?
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Which scientist is credited with providing conclusive evidence against spontaneous generation?
Which scientist is credited with providing conclusive evidence against spontaneous generation?
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What is the primary assertion of the endosymbiotic theory?
What is the primary assertion of the endosymbiotic theory?
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Which scientific theory was widely accepted before the germ theory of disease?
Which scientific theory was widely accepted before the germ theory of disease?
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Which contribution is attributed to Joseph Lister?
Which contribution is attributed to Joseph Lister?
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What was Robert Koch’s significant contribution to medical science?
What was Robert Koch’s significant contribution to medical science?
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Which scientist popularized the cell theory and is known for an essay entitled 'Cellular Pathology'?
Which scientist popularized the cell theory and is known for an essay entitled 'Cellular Pathology'?
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What is the primary function of the nucleolus within a eukaryotic cell?
What is the primary function of the nucleolus within a eukaryotic cell?
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Which component of the endomembrane system is responsible for modifying lipids and proteins?
Which component of the endomembrane system is responsible for modifying lipids and proteins?
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How do peritrichous bacteria primarily move towards chemical attractants?
How do peritrichous bacteria primarily move towards chemical attractants?
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Which of the following structures is NOT typically found in eukaryotic cells?
Which of the following structures is NOT typically found in eukaryotic cells?
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What appearance is present in the rough endoplasmic reticulum, and what is its primary function?
What appearance is present in the rough endoplasmic reticulum, and what is its primary function?
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What is the main function of the cell wall in prokaryotic cells?
What is the main function of the cell wall in prokaryotic cells?
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Which of the following cell shapes corresponds to Trypanosoma?
Which of the following cell shapes corresponds to Trypanosoma?
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Which component is NOT typically part of a prokaryotic cell?
Which component is NOT typically part of a prokaryotic cell?
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What occurs in prokaryotic cells during plasmolysis?
What occurs in prokaryotic cells during plasmolysis?
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What is the function of peroxisomes in eukaryotic cells?
What is the function of peroxisomes in eukaryotic cells?
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What are prokaryotic ribosomes composed of?
What are prokaryotic ribosomes composed of?
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What does the nuclear lamina provide to the eukaryotic nucleus?
What does the nuclear lamina provide to the eukaryotic nucleus?
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What distinguishes the variety of eukaryotic cell shapes?
What distinguishes the variety of eukaryotic cell shapes?
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What eventually happens to a prokaryotic cell in a hypotonic environment?
What eventually happens to a prokaryotic cell in a hypotonic environment?
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Which component is responsible for the rough appearance of the rough endoplasmic reticulum?
Which component is responsible for the rough appearance of the rough endoplasmic reticulum?
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Which of the following structures is involved in the initial stages of sporulation?
Which of the following structures is involved in the initial stages of sporulation?
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In which scenario do prokaryotic cells face crenation?
In which scenario do prokaryotic cells face crenation?
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Which of the following is true regarding the nucleoid region in prokaryotic cells?
Which of the following is true regarding the nucleoid region in prokaryotic cells?
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What characterizes the ribosomes found in prokaryotic cells?
What characterizes the ribosomes found in prokaryotic cells?
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Which of the following bacterial structures is NOT involved in attachment to surfaces?
Which of the following bacterial structures is NOT involved in attachment to surfaces?
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Which bacterial structure is primarily responsible for cell motility?
Which bacterial structure is primarily responsible for cell motility?
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What is the role of the O side chain in lipopolysaccharide (LPS)?
What is the role of the O side chain in lipopolysaccharide (LPS)?
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Which type of flagellar arrangement is characterized by a single flagellum at one end of the cell?
Which type of flagellar arrangement is characterized by a single flagellum at one end of the cell?
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What is the difference between fimbriae and pili?
What is the difference between fimbriae and pili?
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How does the rotation of flagella contribute to bacterial movement?
How does the rotation of flagella contribute to bacterial movement?
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What is the role of chemotaxis in bacterial movement?
What is the role of chemotaxis in bacterial movement?
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A bacterial cell with flagella arranged in a tuft at one end of the cell is called:
A bacterial cell with flagella arranged in a tuft at one end of the cell is called:
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How do capsules contribute to bacterial survival?
How do capsules contribute to bacterial survival?
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Which of the following is NOT a component of a bacterial flagellum?
Which of the following is NOT a component of a bacterial flagellum?
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Study Notes
Microbiology - Chapter 3: The Cell
- Microorganisms vary greatly in size and shape, visually observable microscopically. They also differ in metabolic capabilities.
- Francesco Redi's experiments disproved spontaneous generation for maggots, showing flies were the source.
- John Needham supported spontaneous generation of microbes in broth.
- Lazzaro Spallanzani's experiments challenged Needham's findings, suggesting microbes in the air caused contamination.
- Louis Pasteur conclusively disproved spontaneous generation with swan-neck flasks. He proposed "life only comes from life."
- Robert Hooke first described cells using cork observations, published in Micrographia.
- Rudolf Virchow popularized the cell theory in "Cellular Pathology" (1855), arguing that all cells arise from pre-existing cells.
- Robert Remak's work from 1852 supported the cell origination from other cells.
Endosymbiotic Theory
- Mitochondria and chloroplasts evolved from bacteria.
- These bacteria formed a symbiotic relationship with host cells.
- This relationship led to the evolution of mitochondria and chloroplasts.
Importance of Handwashing
- Ignaz Semmelweis championed handwashing to prevent disease transmission among physicians in the 19th century.
Germ Theory of Disease
- Joseph Lister used antiseptic procedures in surgery, contributing to germ theory acceptance.
- Robert Koch developed a protocol for determining the causes of infectious disease, supporting the germ theory.
Prokaryotic Cell Structure
- Prokaryotic cells lack a nucleus and membrane-bound organelles.
- Their DNA is in a nucleoid region.
- They contain ribosomes (70S).
- Some prokaryotes have a cell wall, maintaining morphology and resisting osmotic changes.
- Possible inclusions to store nutrients.
- Some form endospores to survive harsh conditions.
Prokaryotic Cell Shapes and Arrangements
- Prokaryotes have varied shapes (coccus, bacillus, vibrio, spirillum, spirochete).
- Cells can be arranged in single units, pairs (diplo-), clusters (staphylo-), chains (strepto-), and more.
Prokaryotic Cell Membranes
- Bacterial plasma membrane is a phospholipid bilayer with proteins embedded.
- Some molecules move passively via diffusion. Active transport for larger molecules is common.
- Archaeal membranes are distinct, with ether-linked lipids.
Prokaryotic Cell Envelope
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Cell envelope includes the plasma membrane and a cell wall (typically peptidoglycan in bacteria or pseudopeptidoglycan in archaea).
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Differences exist between gram-positive and gram-negative bacteria, related to the cell wall structure.
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Some bacteria produce glycocalyx coatings like capsules and slime layers aiding in attachment and avoiding the immune response.
Prokaryotic Appendages
- Pili/fimbriae aid in attachments and gene transfer.
- Flagella (including different arrangements) propel movement in water.
- Bacteria use "run-tumble" movements for directed movement.
Eukaryotic Cell Structure
- Eukaryotic cells have a nucleus containing DNA.
- Cytoskeleton provides structural support and transport.
- Components include microfilaments, intermediate filaments, and microtubules.
- Centrosomes are microtubule-organizing centers.
- Mitochondria are complex, double-membraned organelles with cristae for cellular respiration.
- Chloroplasts have thylakoid membranes for photosynthesis.
- Endomembrane system is a series of interconnected membranes (rough ER, smooth ER, Golgi apparatus, peroxisomes) for modifying and transporting materials.
- Ribosomes (80S) are significant for protein synthesis.
Eukaryotic Cell Shapes
- Eukayotic cells can come in numerous shapes and structures, reflecting diversity and specific functions.
- The presence of organelles and other cellular components distinguishes eukaryotic cells from prokaryotic cells.
Eukaryotic Cell Membranes
- Eukaryotic plasma membrane is lipid bilayer with embedded and integrated proteins.
- Contains sterols (like cholesterol) for fluidity maintenance.
- Glycoproteins/glycolipids for recognition and communication.
Transport Across Membranes
- Prokaryotic and eukaryotic cells have varied mechanisms for materials' movement across membranes
- Active and passive transport play roles in movement and maintenance within these cells.
- Endocytosis and exocytosis allow for taking in and releasing large materials into the cell.
Eukaryotic Cell Walls
- Eukaryotic cell walls differ and provide structural support to cells.
- Cell walls are not present in all eukaryotes.
Endospores
- Endospores are features unique to some prokaryote cells.
- The ability to form endospores enables cells to withstand harsh conditions.
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Description
Explore key concepts in microbiology through this quiz focusing on cell theory and early experiments regarding spontaneous generation. Delve into the significant contributions of scientists like Francesco Redi, Louis Pasteur, and Robert Hooke, as well as the endosymbiotic theory that explains the evolution of certain organelles.
